China is stepping up its efforts to rein in the country's Internet, singling out Tencent Holdings Ltd.'s popular news app for spreading vulgar information while shutting down more than 700 websites and thousands of apps in the span of just three weeks.

The Cyberspace Administration of China has scrubbed the web of more than 7 million items since Jan 3, deleting more than 9,300 smartphone apps to screen out information deemed inappropriate or harmful, the watchdog said in a notice distributed to media.

Tencent's Tian Tian Kuai Bao, which means quick daily news, was singled out for spreading "vulgar and low-brow content that was harmful and damaging to the Internet ecosystem" the agency said.

The latest raft of shutdowns, part of a six-month campaign intended to eradicate "vulgarity" from the domestic Internet, stands out for its scale and speed. Baidu Inc. and Sohu.com Ltd. were ordered to suspend a plethora of news services just weeks ago.

Beijing has increasingly taken a hard line as the country's Internet ecosystem flourishes, instigating crackdowns on video games and social media that've hurt industry leaders such as WeChat-operator Tencent and the word's largest startup, Bytedance Ltd.

They represent the most severe digital crackdown in the country's history, shuttering services or temporarily forcing them from app stores for spreading everything from crude jokes to banned information.

Tencent and other websites have been ordered to overhaul their operations, the watchdog said in its notice without elaborating. Its shares fell 0.8 per cent in Hong Kong.

Tencent said it couldn't immediately comment.